This preview shows page 1. Sign up to view the full content.
Unformatted text preview: Sex linkage Among the 23 pairs of chromosomes in human cells, one pair is the sex chromosomes . (The remaining 22 pairs of chromosomes are referred to as autosomes. ) The sex chromosomes determine the sex of humans. There are two types of sex chromosomes: the X chromosome and the Y chromosome. Females have two X chromosomes; males have one X and one Y chromosome. Typically, the female chromosome pattern is designated XX, while the male chromosome pattern is XY. Thus, the genotype of the human male would be 44 XY, while the genotype of the human female would be 44 XX (where 44 represents the autosomes). In humans, the Y chromosome is much shorter than the X chromosome. Because of this shortened size, a number of sex-linked conditions occur. When a gene occurs on an X chromosome, the other gene of the pair probably occurs on the other X chromosome. Therefore, a female usually has two gene of the pair probably occurs on the other X chromosome....
View Full Document
- Fall '07